A gaging system is described in U.S. Pat. No. 4,089,200, assigned to the assignee of this invention, which is especially adapted for use as a back gage with a press brake for positioning metal sheet at intended locations with respect to the press brake dies for forming intended bends at the gaged locations. In the system of that patent, a gage bar is adjustably supported at an intended height with respect to the dies of the associated press brake, and is movable in response to control signals toward or away from the dies to specified gage positions and to define a gaged stop against which a metal sheet is butted in position for a bend to be made.
It is sometimes desirable, as in making return bends in a sheet, to allow pivoting of the gage bar to prevent obstruction by the bar of a sheet being bent, and to prevent damage to the bar by the formed sheet. Back gages and other similar gaging apparatus are known in which pivotable gage bars are employed. As an example, in U.S. Pat. No. 3,812,695, a back gage is described having a gage bar which is upwardly pivotable when subjected to the upward force of an obstructing metal sheet, the bar being returnable by gravity to its normal position after removal of the obstructing force. Pivotable gage stops are also shown in U.S. Pat. Nos. 784,726, 3,421,359 and 3,826,119. In the aforesaid U.S. Pat. No. 4,089,200 of the present assignee, the gage bar itself is not pivotable, but gage finger assemblies are adjustably mountable on the gage bar and which are pivotable to provide a similar function, that is, the provision of gage stops which can be upwardly pivoted to prevent obstruction with a sheet being bent.